Abstract

We present geochemical data of lavas from northwest Africa, allowing us for the first time to carry out large-scale “mapping” of sublithospheric mantle flow beneath the northwest African plate. Our study indicates that Canary mantle plume material traveled laterally along a subcontinental lithospheric corridor (i.e., at depths that are usually occupied by continental lithospheric mantle) more than 1500 km to the western Mediterranean, marking its route over the last 15 m.y. through a trail of intraplate volcanism. A three-dimensional geodynamic reconstruction, integrating results from geophysical studies, illustrates that long-distance lateral flow of mantle material into and through a subcontinental lithospheric corridor can be caused by a combination of (1) deflection of upwelling plume material along the base of the lithosphere, (2) delamination of subcontinental mantle lithosphere beneath northwest Africa, and (3) subduction suction related to the rollback of the subducting oceanic plate in the western Mediterranean. Although the flow of plume material beneath oceanic lithosphere to mid-ocean ridges or along the base of continental rifts has been previously shown, this study demonstrates that plume material can also flow large lateral distances through subcontinental corridors from suboceanic to nonrifting subcontinental settings, generating continental intra-plate volcanism without the need for a plume to be located directly beneath the continent.

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